Proteoglycans are ubiquitous components of connective tissues. They often occur as major components of the extra-cellular matrix of these tissues. Cartilage proteoglycans have been the most thoroughly studied and they have served as a useful model for examining proteoglycan structure and function in other more complex connective tissue matrices. Detailed analysis of proteoglycan structure by conventional biochemical procedures has been complicated by the inherent heterogeneity and polydisperisty of the proteoglycans themselves. Immunological methods offer the possibililty of raising antibodies which specifically recognize different antigenic determinants present on proteoglycans and link protein. The recent introduction of monoclonal antibody procedures has offered the possiblity of producing antibodies which specifically recognize structural and functional antigenic determinants on biological macromolecules. In this proposal we plan to produce and characterize monoclonl antibodies that recognize specific determinants on proteoglycan and link protein. The specificity of the antibodies will be determined using biochemical methods, and in immunoassay procedures. Specific antibodies will be applied to problems of quantitating, identifying, purifying and determining the tissue distribution of proteoglycan and link protein. Both immunochemical studies on isolated material and immunohistochemical procedures will be employed. A major objective of this proposal is to use specific monoclonal antibodies as a means of characterizing and purifying peptide fragments of link protein and proteoglycan. These peptides will be used in the determination of the amino acid sequences (primary structure) of link protein and lproteoglycan. In addition, antibodies recognizing functional aspects of proteoglycan and link protein interactions will be used instudies determining structure function relationships involved in proteoglycan aggregate formation. A longer term objective is to extend these studies to gain a better understanding of proteoglycan metabolism in other more complex connective tissues. These studies will increase our knowledge of connective tissue function in normal conditions and in disease.